Nontraumatic aneurysm rupture following an endoscopic third ventriculostomy and ventricular drainage: Case report of a rare complication.

Background: Although endoscopic third ventriculostomy is a safe procedure, the authors report a case of aneurysmal subarachnoid hemorrhage as an unusual and serious complication of an endoscopic third ventriculostomy and ventricular drainage.

Case Description: A 60-year-old male presented with obstructive hydrocephalus caused by midbrain tumors was admitted to our hospital. Endoscopic third ventriculostomy and external ventricular drainage were successfully performed. Two days after the operation, he became comatose, and a computed tomography (CT) scan revealed a diffuse subarachnoid hemorrhage. Emergency cerebral angiogram showed an aneurysm of the left internal carotid artery. Endovascular coil embolization of the ruptured aneurysm was then performed.

Conclusion: The rupture of the aneurysm may have been induced by excessive cerebrospinal fluid drainage after the endoscopic third ventriculostomy. Planning for intracranial endoscopic procedures should consider that rupture of an unknown previously unruptured aneurysm is a possible complication.